Quote:
Originally Posted by E92Fan
Firstly, the Fuchs oil is a 5W-40 - it is only thicker than the standard BMW Castrol oil at higher operating temperatures.
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Quote:
Originally Posted by E92Fan
The damage to my engine has nothing at all to do with cold wear - it has to do with the pistons getting too hot and swelling, therefore scoring the cylinder walls.
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OK. So, could the problem be that the oil is thicker at higher operating temps?
Please bear in mind that I have little knowledge of fluid dynamics and continually bow to your knowledge of all things N54 Tony - however, I would like to explore whether this hypothesis holds water.
If the problem is due to pistons getting too hot, expanding and scoring the cylinder walls, this surely points towards a lubrication issue. The purpose of engine oil being to lubricate all moving parts, preventing metal:metal contact, generating too much friction/heat and damaging components.
So, could this be due to the following conditions / characteristics of your engine:
1) Blueprinted engine = tighter tolerances between moving parts than a stock N54.
2) 5w-40 oil = thicker engine oil at high temps = less flow to moving parts at high temps then with recommended 5w-30 oil.
3) Sustained track use = sustained higher temps then would be experienced then 99.9% of N54s on the road.
Could these circumstances lead to expanded pistons, even tighter tolerances, less flow of thicker engine oil to components, more friction, increased heat and so on?
If so, this would become a vicious circle of friction, heat, lack of lubrication leading to this type of engine wear.
After the initial premature engine wear, once cooled, the tolerances between pistons and cylinder wall would become larger increasing blow by and carbonisation.
Out of interest - which catch can are you running?